Assay Cartridge Valve System

ABSTRACT

Assay cartridges are described that have a plurality of chambers and a fluidic network that includes fluidic conduits and a multi-port valve designed to selectively connect the valve inlet and one valve outlet through a fluidic connector in the valve as the remaining valve outlets are sealed.

CROSS-REFERENCE TO RELATED APPLICATION

Reference is made to copending application Ser. No. 13/343,834, filedJan. 5, 2012 and Ser. No. 12/959,952, filed Dec. 3, 2010. Thedisclosures of each of these applications are incorporated herein byreference.

STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH

This invention was made with federal support under Contract No.W81XWH-10-20155 awarded under the U.S. Army Medical Research AcquisitionAct. The U.S. government has certain rights in the invention.

FIELD OF THE INVENTION

This application relates to apparatuses incorporating multi-port valvesand methods of using such apparatuses for conducting chemical,biochemical and/or biological assays on a sample.

BACKGROUND OF THE INVENTION

Clinical measurements have been traditionally carried out in centralclinical labs using large clinical analyzers that can handle largenumbers of samples in batch mode. These laboratories are staffed bytrained personnel that are capable of maintaining and running thesecomplex analyzers. There is a growing desire to move clinicalmeasurements from the central lab to the “point of care”, e.g., theemergency room, hospital bedside, physicians office, home, etc. Point ofcare measurements allow a care provider or patient to quickly makedecisions based on diagnostic information, as opposed to having to waithours or days to receive laboratory results from a clinical lab. Thedifficulty in developing point of care diagnostic systems has beenmaking them small enough and easy enough to use so that they can be usedby unskilled operators in decentralized clinical settings, but at thesame time maintaining the low cost, diverse assay menu, and/or highperformance of tests carried out on traditional clinical analyzers incentral laboratories.

In addition, certain types of tests carried out in point of carediagnostic systems involve a series of complex processes that can behampered by the presence of contaminants in the system. For certaintypes of tests, e.g., polymerase chain reaction (PCR), the allowablelevels of contamination are very low, typically one part in 10,000.There is a need for a point of care system that can conduct complexmulti-step processes with minimal contamination from one step to thenext.

SUMMARY OF THE INVENTION

The invention provides an assay cartridge comprising: (a) a plurality ofchambers, and (b) a fluidic network including: (i) a plurality offluidic conduits connecting the plurality of chambers; and (ii) amulti-port valve comprising:

-   -   (x) a cap;    -   (y) a stator comprising a rotor engagement member, a valve        inlet, and a plurality of valve outlets accessible to one or        more fluidic conduits in the fluidic network; and    -   (z) a rotor biased toward the stator and comprising a sealing        member disposed between the rotor and the stator, a spring, and        a stator engagement member configured to disengage the rotor        when the stator engagement member is in communication with the        rotor engagement member,    -   wherein, when engaged, the rotor is rotated to fluidically        connect the valve inlet to one of the valve outlets through a        fluidic connector on the rotor while the sealing member seals        the remaining valve outlets.

In one embodiment the spring comprises a top surface, a bottom surface,a cylindrical body comprising a central vertical axis disposed betweenthe top and bottom surfaces and a plurality of pairs of axially spacedradially extending grooves surrounding the central vertical axis, and aplurality of through-holes intersecting the central vertical axis at aposition perpendicular to the intersection of the plurality of pairs ofgrooves to the central vertical axis. In this regarding, the pluralityof pairs of grooves and the plurality of through-holes define aplurality of ribs in the cylindrical body. In a preferred embodiment,the spring is an integrated spring, e.g., a corrugated stem.

The multi-port valve of the assay cartridge of the invention canselectively open one of the plurality of valve outlets by (a) rotatingthe rotor via engagement between an instrument stepper motor (a driveelement) and the instrument interface element, and (b) disengaging thestator and rotor engagement members, thereby fluidically connecting thevalve inlet to one of the plurality of valve outlets through the fluidicconnector and sealing the remaining valve outlets via compression of thesealing member against the stator.

The invention also includes a method of using a multi-port valve in anassay cartridge, wherein the cartridge comprises a plurality of chambersand a fluidic network including (i) a plurality of fluidic conduitsconnecting the plurality of chambers; and (ii) a multi-port valvecomprising:

-   -   (x) a cap;    -   (y) a stator comprising a rotor engagement member, a valve        inlet, and a plurality of valve outlets accessible to one or        more fluidic conduits in the fluidic network; and    -   (z) a rotor biased toward the stator and comprising a sealing        member disposed between the rotor and the stator, a spring, an        instrument interface element, and a stator engagement member        configured to disengage the rotor when the stator engagement        member is in communication with the rotor engagement member,    -   the method comprising the steps of:    -   (a) contacting the instrument interface element with an        instrument stepper motor;    -   (b) rotating the rotor to disengage the rotor and stator        engagement members;    -   (c) connecting, fluidically, the valve inlet to one of the valve        outlets through a fluidic connector on the rotor; and    -   (d) sealing the remaining valve outlets by contacting the        sealing member to the stator.

Further provided is a method of moving fluid in an assay cartridgecomprising a plurality of chambers and a fluidic network including aplurality of fluidic conduits connecting the plurality of chambers and amulti-port valve having:

-   -   (x) a cap;    -   (y) a stator comprising a rotor engagement member, a valve        inlet, and a plurality of valve outlets accessible to one or        more fluidic conduits in the fluidic network; and    -   (z) a rotor biased toward the stator and comprising a sealing        member disposed between the rotor and the stator, a spring, an        instrument interface element, and a stator engagement member        configured to disengage the rotor when the stator engagement        member is in communication with the rotor engagement member,    -   the method comprising the steps of:    -   (a) introducing a fluid slug into the fluidic network;    -   (b) applying, selectively, pressure or vacuum at one or more        fluidic junctions in the fluidic network to move the fluid slug        through the fluidic network; and    -   (c) directing movement of the fluid slug through the fluidic        network by engaging the multi-port valve to fluidically connect        the valve inlet to one of the valve outlets through a fluidic        connector on the rotor while the sealing member seals the        remaining valve outlets.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a simplified pictorial representation of acartridge-based assay module incorporating a multi-port valve of theinvention.

FIGS. 2( a)-(i) show various embodiments of a multi-port valve. FIGS. 2(a)-(b) illustrate a multi-port valve that interfaces with a plurality ofchannels or conduits in a cartridge fluidic network to direct the flowof fluid from one of a plurality of channels to a single valve inlet(FIG. 2( a)) or from a single valve inlet to one of a plurality ofoutlets (FIG. 2( b)). FIGS. 2( c)-(d) show how fluid is directed in amulti-port valve from a valve inlet to one of a plurality of valveoutlets and, upon rotation of the valve, to an adjacent outlet.Likewise, FIGS. 2( e)-(f) show how fluid can be directed in a multi-portvalve from one valve outlet (G) to an adjacent valve outlet (H) and,upon rotation of the valve, from an adjacent valve outlet (H) to anadditional valve outlet (I). FIGS. 2( g)-(i) show various alternativeembodiments for the connection of multi-port valves in series.

FIGS. 3( a)-(c) illustrate the components of a multi-port valve, i.e., acap, a spring, rotor, and stator and FIGS. 3( b)-(c) provide a detailedview of the fluidic channel between the rotor and the sealing member.

FIG. 4 shows the results of an experiment conducted to determine theamount of carryover in a multi-port valve. The amount of carryover wasdetermined by flowing a buffer with free, unbound label through thevalve and then measuring the amount of label in successive wash slugs.The graph shows that an approximate five-fold dilution factor isachievable with each round of washing (after the first cycle), and awash quality of 10,000 is achievable with 5-6 washes.

FIGS. 5( a)-(j) show the components of the valve and provide a detailedillustration of the design of the spring and the instrument interfaceelement. FIG. 5( a) provides a detailed view of the retention cap,rotor, and stator, while FIGS. 5( b)-(d) show the instrument interfaceelement and the spring from various vantage points. FIGS. 5( e)-(g) showvarious embodiments of the instrument interface element and FIGS. 5(h)-(j) illustrate the corresponding instrument engagement element andhow the stepper motor (drive element) engages with the instrumentinterface element.

FIG. 6( a)-(g) show the storage elements of the rotor and stator, i.e.,the stator engagement member and the rotor engagement member,respectively. FIGS. 6( b)-(e) illustrate how the rotor and statorengagement members communicate to engage/disengage the rotor from thestator and FIGS. 6( f)-(g) illustrate an alternate embodiment of thestorage elements and communication between the stator and rotorengagement members.

DETAILED DESCRIPTION

The invention, as well as additional objects, features and advantagesthereof, will be understood more fully from the following detaileddescription of certain preferred embodiments. Unless otherwise definedherein, scientific and technical terms used in connection with thepresent invention shall have the meanings that are commonly understoodby those of ordinary skill in the art. Further, unless otherwiserequired by context, singular terms shall include pluralities and pluralterms shall include the singular. The articles “a” and “an” are usedherein to refer to one or to more than one (i.e., to at least one) ofthe grammatical object of the article. By way of example, “an element”means one element or more than one element.

The invention relates to a multi-port valve that can be used in an assaycartridge to facilitate fluid isolation in and selective fluidiccommunication throughout the cartridge fluidic network. An assaycartridge of the invention incorporates one or more fluidic componentssuch as compartments, wells, chambers, fluidic conduits, fluidports/vents, filters, valves, and the like and/or one or more detectioncomponents such as electrodes, electrode contacts, sensors (e.g.,electrochemical sensors, fluid sensors, mass sensors, optical sensors,capacitive sensors, impedence sensors, optical waveguides, etc.),detection windows (e.g., windows configured to allow opticalmeasurements on samples in the cartridge, such as absorbance, lightscattering, refraction, or reflection, fluorescence, phosphorescence,chemiluminescence, electrochemiluminescence, etc.), and the like. Acartridge can also comprise reagents for carrying out an assay such asbinding reagents, detectable labels, sample processing reagents, washsolutions, buffers, etc, and the reagents can be present in liquid form,solid form and/or immobilized on the surface of solid phase supportspresent in the cartridge. Certain preferred cartridge embodiments alsocomprise detection chambers having the electrode arrays and/or bindingdomains. The incorporation of the disclosed multi-port valve into anassay cartridge reduces the volume over which vacuum pressure builds inthe fluidic network and potential contamination.

FIG. 1 depicts a simplified schematic of a cartridge-based biochemicaldetection system (100) that incorporates a multi-port valve (101). Inthe embodiment shown in FIG. 1, the cartridge includes one or morefluidic components (102, 105 and 107) that are linked to each otherthrough a multi-port valve (101) and can also include fluidic conduitslinking these components to additional components, as exemplified, bythe connection of component (107) to additional fluidic components (103)and (104) (chambers (103) and (104) are connected via a T-junction inFIG. 1, but it is not necessary to connect these chambers in thisfluidic configuration; in addition, the waste chamber (104) can bepositioned on either side of the detection chamber (103)). Fluidiccomponents that can be linked in this manner include sample introductionchambers, solid and liquid reagent storage chambers, reaction chambers,mixing chambers, filters, valves, and detection chambers and otherfluidic components known in the art of fluidic assay devices. Thecartridge can also include vent ports (106) in fluidic communicationwith the fluidic components (directly or through vent conduits) so as toallow the equilibration of fluid in the component with the atmosphere orto allow for the directed movement of fluid into or out of a specifiedchamber by the application of positive or negative pressure. Themulti-port valve allows for the selective movement of fluid between thechambers linked to the valve and, in the case of cartridge (100), theselective movement of fluid from component (107) to component (102) orone of components (105) and/or the selective movement of fluid tocomponent (107) from component (102) or one of components (105).

In one specific embodiment, the cartridge has sample chambers (102), oneor more detection chambers (103) (preferably, detection chambers adaptedfor use in electrochemiluminescence measurements) and one or more wastechambers (104). The sample chamber is connected by a fluid conduit (A)directed through a multi-port valve (101) so that a sample introducedinto a sample chamber can be delivered through a conduit (F) in thefluidic network into one or more detection chambers for analysis andthen passed into one or more waste chambers for disposal (as shown inthe embodiment in FIG. 1, a filter (107) is incorporated into thefluidic path downstream of conduit F). Preferably, this cartridge alsoincludes one or more reagent chambers (105) for storing liquid reagents,the reagent chambers are connected via conduits (B-E) through themulti-port valve to the other components so as to allow the introductionof the liquid reagents into specified sample or detection chambers. Thevent ports (106) are in fluidic communication with the sample, reagent,detection and/or waste chambers (directly or through vent conduits).

In a preferred embodiment of the invention, an assay cartridge hasminimal or no active mechanical or electronic components. When carryingout an assay, such an assay cartridge may be introduced into a cartridgereader which provides these functions. For example, a reader may haveelectronic circuitry for applying electrical energy to the assayelectrodes and for measuring the resulting potentials or currents atassay electrodes. The reader may have one or more light detectors formeasuring luminescence generated at assay electrodes. Light detectorsthat may be used include, but are not limited to photomultiplier tubes,avalanche photodiodes, photodiodes, photodiode arrays, CCD chips, CMOSchips, film. The light detector may be comprised within an opticaldetection system that also comprise lenses, filters, shutters,apertures, fiber optics, light guides, etc. The reader may also havepumps, valves, heaters, sensors, etc. for providing fluids to thecartridge, verifying the presence of fluids and/or maintaining thefluids at an appropriate controlled temperature. The reader may be usedto store and provide assay reagents, either onboard the reader itself orfrom separate assay reagent bottles or an assay reagent storage device.The reader may also have cartridge handling systems such as motioncontrollers for moving the cartridge in and out of the reader. Thereader may have a microprocessor for controlling the mechanical and/orelectronic subsystems, analyzing the acquired data and/or providing agraphical user interface (GUI). The cartridge reader may also compriseelectrical, mechanical and/or optical connectors for connecting to thecartridge. The reader can also include motors and mechanical couplingsto drive the movement of integrated valves in the cartridge.

An assay cartridge of the invention can be configured to conduct amultiplexed immunoassay and/or nucleic acid measurement on a biologicalfluid sample. With respect to assay cartridges configured to conductmultiplexed nucleic acid and immunoassay methods, reference is made tocopending application Ser. No. 13/343,834, filed Jan. 5, 2012, and Ser.No. 12/959,952, filed Dec. 3, 2010, respectively, the disclosures ofwhich are incorporated herein by reference in their entireties.

In a preferred embodiment, the assay cartridge includes a plurality ofchambers and a fluidic network including a plurality of fluidic conduitsconnecting the plurality of chambers and a multi-port valve configuredfor fluid isolation and selective communication between fluidic conduitsin the network. In certain embodiments, it is desirable to reduce oreliminate fluid contamination within the fluidic network of an assaycartridge, e.g., in those embodiments where contaminants can inhibitprocesses that occur downstream in the cartridge. For example, in anassay cartridge configured to analyze nucleic acid in a sample by apolymerase chain reaction (PCR), it is beneficial to avoid contaminationof eluate after nucleic acid purification because contaminants caninhibit downstream processes like reverse transcription (RT) and PCRamplification. Such contaminants include but are not limited to lysisbuffers like guanidine isothiocyanate (GuSCN), wash buffers, such asethanol, hemoglobin from a blood sample, or humic acid from a soilsample. The placement of filters in the fluidic network to preventcontaminants from interfering with downstream processes can reducecontamination, but elevated pressures can develop in the fluidicnetwork. In addition, vacuums can be generated downstream of the filtersbefore liquid breaks through, with the trapped vacuum resulting inpotential contamination of downstream processes.

This issue is addressed by the incorporation of a multi-port valve inthe fluidic network of the cartridge, as shown in FIGS. 2( a)-(b), withthe ability to selectively connect one or more conduits in a fluidiccircuit, isolating the remaining conduits and mitigating developingvacuum pressure in the network as well as reducing potentialcontamination. A multi-port valve such as that described and claimedalso minimizes carryover and contamination from processes conductedupstream of the valve in the fluidic network. Still further, the use ofa multi-port valve reduces dead volume in the fluidic circuit toincrease fluidic processing and it also maintains a seal underrelatively high pressures. The dead volume is reduced in the valve byminimizing the distance and internal volume between the inlet and theoutlets.

As shown in FIG. 2( a), the multi-port valve can be incorporated into afluidic network to interface with a plurality of conduits (A-E) toisolate and direct fluid from one conduit of the plurality into a commonchannel or conduit (F). A valve of this configuration can be used toconnect upstream cartridge components, e.g., reagent chambers, to asingle downstream conduit. An alternate configuration is shown in FIG.2( b), in which the valve directs fluid from a valve inlet (F) to one ormore of a plurality of conduits (G-K). As shown in FIGS. 2( c)-(d), whenthe inlet (F) is connected to one of the outlets in the fluidic network,e.g., G, the remaining outlets are disconnected from the inlet, and whenthe valve is rotated to connect the inlet to another outlet in thenetwork, e.g., H, the fluidic connection between F and G is disconnectedand the remaining outlets remain disconnected from the inlet. A furtherembodiment is shown in FIG. 2( e), in which one of the plurality ofconduits (G) in the fluidic network is connected to another of theplurality of conduits (H). When the valve is rotated, as in FIG. 2( f),the fluidic connection between conduits (G) and (H) is disconnected anda connection between conduits (H) and (I) is established.

One or more multi-port valves can be included in an assay cartridge. Inone embodiment, up to 20 outlets can be included in an assay cartridge,preferably up to 10 outlets, and more preferably up to 6 outlets can beincluded in an assay cartridge. For those embodiments in which two ormore valves are included in a cartridge, the valves can be connected inparallel or in series. Various alternative embodiments for theconnection of two or more valves in series in a cartridge areillustrated in FIGS. 2( g)-(i). For example, the inlet of one valve canbe connected to the common port of a proximate valve (FIG. 2( g)), oneof the plurality of valve outlets of one valve can be connected to theinlet of a proximate valve (FIG. 2( h)), and/or one of the plurality ofvalve outlets of one valve can be connected to one of the plurality ofoutlets of a proximate valve (FIG. 2( i)).

A more detailed view of the multi-port valve is shown in FIG. 3( a). Themulti-port valve includes a cap (301), a stator (302), and a rotor(303). The stator comprises a rotor engagement member (not shown), avalve inlet (304), and a plurality of valve outlets accessible to one ormore fluidic conduits in the fluidic network (305). The outlets arepreferably positioned at a fixed radius from the valve inlet, preferablyabout 0.1 to about 0.4 inches (preferably the internal volume of thefluidic connector between the valve inlet and outlets is less than 10 uLand preferably less than 5 uL). The rotor is biased toward the statorand includes a sealing member (306) disposed between the rotor and thestator, a spring (307), and a stator engagement member (308) incommunication with the rotor engagement member. When engaged, the rotoris rotated to fluidically connect the valve inlet to one of the valveoutlets through a fluidic connector on the rotor while the sealingmember seals the remaining valve outlets. A detailed view of the sealingmember (306) is shown in FIGS. 3( b)-(c). FIG. 3( b) shows the sealingmember separated from the rotor (303) to show the fluidic connector(309) on the rotor which comprises a channel between the valve inlet(310) and the connecting port (311). The sectioned view in FIG. 3( c)shows the fluidic connector (309) in more detail, illustrating how thechannel is formed between the base of the rotor and the sealing memberto connect the valve inlet to the connecting port.

The valve provides the ability to switch flow directions with accuratecontrol and low dead volume (the internal dead volume is less than about10 uL, preferably about 7 uL). Rotors, as described herein, with threedifferent hardness/elasticity properties were tested (38 A, 49 A and 59A durometer on the Shore scale). The integrity of the seal was checkedby sealing the valve outlets, pressurizing the valve inlet to about 10psi, and measuring the pressure decay rate. The 59 A elastomer created agood seal under spring forces greater than 1 lb with air pressure decayrates of less than 0.1 psi/30 seconds. The torque required to actuatethe rotor with a sealing spring force of 1.5 lbs was measured to be lessthan 3 oz-in. The amount of liquid carryover in the valve was alsomeasured and is shown in FIG. 4. A wash quality of about 1:10,000 with5-6 washes (each wash was about 50 uL) was achieved using the multi-portvalve of the present invention.

In one embodiment, the multi-port valve includes a spring (307) which ispreferably disposed between the rotor and cap as shown in FIG. 3( a).FIG. 5( a) illustrates another embodiment where the spring is integratedinto the structure of the rotor and an expanded view of one embodimentof the spring is shown in FIGS. 5( b)-(d). The spring (307) includes atop surface (501), a bottom surface (502), a cylindrical body (503)comprising a central vertical axis (504) disposed between the top andbottom surfaces and a plurality of pairs of axially spaced radiallyextending grooves (505-508) surrounding the central vertical axis, and aplurality of through-holes (509-511) intersecting the central verticalaxis at a position substantially perpendicular to the intersection ofthe plurality of pairs of grooves to the central vertical axis. Theunique configuration of paired grooves and through-holes define aplurality of ribs in the cylindrical body that provides a spring forceto the spring, preferably between about 0.5-5.0 lbs, and more preferablyabout 2.5 lbs. The design illustrated in FIG. 5( a)-(d) enablesmanufacture of the spring via injection molding. In one embodiment, thespring is an integrated spring, e.g., a corrugated stem.

The rotor also includes an instrument interface element (512), e.g., onthe top surface of the rotor configured to communicate with a driveelement of a stepper motor in an instrument. When the instrument steppermotor and interface element are engaged, the stepper motor can index therotor through the different fluidic ports on the stator. As illustratedin FIGS. 5( e)-(j), the rotor includes an instrument interface elementon the top surface of the rotor that includes a slot configured tocommunicate with a stepper motor in an instrument and when engaged, thestepper motor can index the rotor through the different fluidic outletson the stator. The instrument interface element can include one or morepin engagement holes or slots configured to communicate with one or moredrive elements (e.g., pins) in the stepper motor. Alternatively, theinstrument interface element includes a multi-blade engagement slotconfigured to communicate with a multi-lobe drive element in the steppermotor. Various embodiments of an instrument interface element are shownin FIGS. 5( e)-(g) and the engagement of the instrument interfaceelement by an instrument stepper motor is illustrated in FIGS. 5(h)-(i). As shown in FIG. 5( e), in one embodiment, the instrumentinterface element comprises a slot, preferably a symmetric slot and thedrive blade can be engaged 180° out of phase. Alternatively, as shown inFIG. 5( f), one or more pin engagement holes are used as an instrumentinterface element. The locations of the holes are not symmetric aboutthe axis of the valve and therefore, there is only one orientation inwhich the pins can be engaged to insure proper clocking of thevalve/driver interface. In another embodiment shown in FIG. 5( g), theinstrument interface element comprises a three blade interface whichprovides a single orientation in which the stepper motor can be engaged.Preferably, the instrument interface element includes a three-bladeengagement slot and the multi-lobe drive element comprises three lobesthat can interface with the three-blade engagement slot. Mostpreferably, the lobes are non-rotationally symmetric, i.e., there is asingle position per revolution in which the lobes and slots can engage.As illustrated in FIG. 5( h)-(j), the instrument drive interface (513)has a corresponding engagement element, i.e., an element configured tomate with the configuration of the instrument interface element of thevalve (512). The instrument drive interface is preferably spring loaded.If the rotor and instrument drive interface are in phase, they willengage and if they are out of phase, then the over-travel spring willcompress and prevent the instrument from locking so that the instrumentdrive interface can be rotated once more to engage and fully mate withthe rotor.

The multi-port valve includes rotor and stator engagement members thatcommunicate to (a) raise the rotor off the stator during storage orother periods of non-use, preventing compression set during long termstorage, and (b) lower the rotor to the appropriate position on thestator during use. The stator engagement member engages the rotorengagement member at a defined rotational position. A non-limitingexample of the communication between the rotor and stator engagementmembers is illustrated in FIGS. 6( a)-(e). The stator and rotorengagement members (601 and 602), respectively the stator engagementmember is also shown in FIG. 3 as element (308)) are configured to movethe rotor away from and towards the stator to disengage and engage thestator and rotor, respectively. In the embodiment depicted in FIG. 6(a)-(e), the stator engagement element (601) comprises a tab and therotor engagement element (602) comprises a ramp and the tab is designedto ride on the ramp to move the rotor away from or towards the stator.As shown in FIG. 6( b), the ramp includes a first slope (603) and asecond slope (604) where one slope goes up and the other goes down.Preferably, a rest area having substantially no slope is disposedbetween the first and second slope tab (601) rides upward on one of theslopes to move the rotor away from the stator and the tab rides downwardon the other slope to move the rotor toward the stator. When not in use,tab (601) may rest on the rest area between the first and second slope.FIGS. 6( a)-(e) illustrate one non-limiting embodiment of thecommunication between the rotor and stator engagement members. It willbe understood by the skilled artisan that the shape of the statorengagement member and the relative upward and downward slope of therotor engagement member can be adjusted without departing from thespirit or scope of the invention. In addition, alternative embodimentsare also within the scope of the invention. For example, as shown inFIG. 6( f), the stator engagement member can comprise a tab and therotor engagement member can comprise a ledge configured to receive andlock the tab in place, reversibly or irreversibly (in one embodiment,engagement of a tab and ledge can be reversed, e.g., by pulling on therotor against the spring by an external means, e.g., via a bayonet styleinterlocking interface). FIG. 6( g) shows the tab and ledge disengaged.

The valve can selectively open one of the plurality of valve outlets by(a) rotating the spring via engagement between the instrument steppermotor and the instrument interface element on the top surface of therotor, and (b) disengaging the stator and rotor engagement members,thereby fluidically connecting the valve inlet to one of the pluralityof valve outlets through the fluidic connector and sealing the remainingvalve outlets via compression of the sealing member against the stator.In one embodiment, the rotor is rotated to fluidically connect the valveinlet to two or more outlets while the remaining valve outlets aresealed by the sealing member. In a preferred embodiment, the multi-portvalve includes one stator and corresponding rotor engagement member.Alternatively, the valve can include a plurality of stator andcorresponding rotor engagement members, e.g., depending on the diameterof the valve and the relative need to evenly distribute the engagementmember lifting forces to prevent the rotor from binding duringdisengagement.

In one embodiment, the multi-port valve selectively opens one of theplurality of valve outlets by (a) rotating the spring via engagementbetween an instrument stepper motor and the instrument interface elementon the top surface of the rotor, and (b) disengaging the stator androtor engagement members, thereby fluidically connecting the valve inletto one of the plurality of valve outlets through a fluidic connector andsealing the remaining valve outlets via compression of the sealingmember against the stator.

The transition of the rotor and stator engagement members from engaged(for storage) to disengaged (in which the sealing member makes fullcontact with the stator) is illustrated in FIGS. 6( b)-(e). In FIG. 6(b), the tab (601) and ramp (602) are fully engaged, producing a space(605) between the rotor and stator to fully disengage the seal from thestator. In FIG. 6( c), as the tab moves from the top of the ramp downthe downward slope, the space (605) between the rotor and statordecreases. As shown in FIG. 6( d), as the tab moves further down thedownward slope, the space (605) decreases still further until thetab/ramp reaches the fully disengaged position, at which point the sealis fully engaged with the stator (shown in FIG. 6( e)).

Therefore, a multi-port valve can be used in an assay cartridge bycontacting the instrument interface element of the rotor with aninstrument stepper motor, rotating the rotor to disengage the rotor andstator engagement members, fluidically connecting the valve inlet to oneof the valve outlets through a fluidic connector on the rotor, andsealing the remaining valve outlets by contacting the sealing member tothe stator. In a preferred embodiment, the stator includes one or morealignment guides that are used to align the stator within the instrumentto insure appropriate alignment of the valve and stepper motor in theinstrument. The rotating step commences by compressing the sealingmember against the stator by disengaging the stator and rotor engagementmembers, as illustrated in FIGS. 6( b)-(e), while the fluidic connectingselection step includes rotating the rotor to the appropriate positionso the valve inlet and valve outlets are aligned as necessary.

The invention further provides a method of moving fluid in an assaycartridge including a multi-port valve of the invention that comprisesthe steps of (a) introducing a fluid slug into a fluidic network in thecartridge, (b) selectively applying pressure at one or more fluidicjunctions in the fluidic network to move the fluid slug through thefluidic network, and (c) directing movement of the fluid slug throughthe fluidic network by engaging the multi-port valve to fluidicallyconnect the valve inlet to one of the valve outlets through a fluidicconnector on the rotor while the sealing member seals the remainingvalve outlets.

The positioning, configuration, geometry, and manufacture of fluidicconduits in the cartridge that interface with the multi-port valvedescribed herein are described in paragraphs 228-286 and theaccompanying figures of U.S. Application Publication No. 2011/0201099.Non-limiting examples of an immunoassay cartridge that can include themulti-port valve of the invention are described in paragraphs 180-286and illustrated, inter alia, in FIGS. 9-22 of U.S. ApplicationPublication No. 2011/0201099 (the identified disclosures of U.S. App.Pub. No. 2011/0201099 is incorporated herein by reference in itsentirety). Likewise, non-limiting examples of a PCR cartridge that caninclude the multi-port valve of the invention are illustrated, interalia, in FIGS. 1-4 and 6(c), and in the accompanying description onpages 10-50 and of U.S. application Ser. No. 13/343,834, filed Jan. 5,2012 (the identified disclosure of U.S. Ser. No. 13/343,834 isincorporated herein by reference in its entirety).

The fluidic components are preferably designed and incorporated into thecartridge body to form the fluidic network using certain predefineddesign guidelines. The design guidelines for each component can bedependent upon one or more factors such as, e.g., cartridge body design(i.e., single-piece body, multiple piece body, modular body, single readchamber, multiple read chamber, and the like), manufacturing process(e.g., injection molding, blow molding, hot stamping, casting,machining, ultrasonic welding, laser welding, radio-frequency welding,etc.), materials (e.g., polycarbonate, acrylic, PVDF, PET, polystyrene,polypropylene, thermoplastic elastomer (TPE) and the like), assayrequirements (e.g., binding assay, competitive binding assay, singlestep assay, two-step assay, etc.), functional requirements (e.g., samplesize, assay reagent volumes, detection technology, time-to-result,incubation, heating, mixing/agitating), safety/handling requirements(e.g., self-containment, regulatory approval, ease of use, etc.), and/orthe like.

In one preferred embodiment, the rotor is a unitary element includingthe spring and stator engagement member and the sealing member isattached to that unitary element. The rotor unitary element and/or thesealing member can be injection molded, with the sealing memberover-molded to the bottom surface of the rotor unitary element. In analternative embodiment, the rotor can be manufactured by laser weldingor another similar process to define buried channels, with anover-molded sealing member on the bottom surface.

The skilled practitioner will be able to readily select materialssuitable for the fabrication of the cartridges and multi-port valves ofthe invention. Suitable materials include glass, ceramics, metals and/orplastics such as acrylic polymers (such as Lucite), acetal resins (suchas Delrin), polyvinylidene fluoride (PVDF), polyethylene terephthalate(PET), polytetrafluoroethylene (e.g., Teflon), polystyrene,polycarbonate, polypropylene, ABS, PEEK, thermoplastic elastomer (TPE)and the like. Preferably, the materials are inert to anysolutions/reagents that will contact them during use or storage of thecartridge. In a preferred embodiment, the cartridge body comprisespolycarbonate and the sealing member comprises thermoplastic elastomer.

The present invention is not to be limited in scope by the specificembodiments described herein. Indeed, various modifications of theinvention in addition to those described herein will become apparent tothose skilled in the art from the foregoing description and accompanyingfigures. Such modifications are intended to fall within the scope of theclaims. Various publications are cited herein, the disclosures of whichare incorporated by reference in their entireties.

What is claimed is:
 1. An assay cartridge comprising: a) a plurality ofchambers; and b) a fluidic network including i) a plurality of fluidicconduits connecting said plurality of chambers; and ii) a multi-portvalve comprising: (y) a stator comprising a rotor engagement member, avalve inlet, and a plurality of valve outlets accessible to one or morefluidic conduits in said fluidic network; and (z) a rotor biased towardsaid stator and comprising a sealing member disposed between said rotorand said stator, a spring, and a stator engagement member configured todisengage said rotor when said stator engagement member is incommunication with said rotor engagement member, wherein, when engaged,said rotor is rotated to fluidically connect said valve inlet to one ofsaid valve outlets through a fluidic connector on the rotor while saidsealing member seals the remaining valve outlets.
 2. The assay cartridgeof claim 1 wherein said spring is disposed between said rotor and saidcap.
 3. The assay cartridge of claim 1 wherein said spring comprises atop surface, a bottom surface, a cylindrical body comprising a centralvertical axis disposed between said top and bottom surfaces and aplurality of pairs of axially spaced radially extending groovessurrounding said central vertical axis, and a plurality of through-holesintersecting said central vertical axis at a position perpendicular tothe intersection of said plurality of pairs of grooves to said centralvertical axis.
 4. The assay cartridge of claim 3 wherein said pluralityof pairs of grooves and said plurality of through-holes define aplurality of ribs in said cylindrical body.
 5. The assay cartridge ofclaim 1 wherein said spring comprises a corrugated stem.
 6. The assaycartridge of claim 1 wherein said spring has a spring force betweenabout 0.5-5.0 lbs.
 7. The assay cartridge of claim 1 wherein said springhas a spring force between about 2.5 lbs.
 8. The assay cartridge ofclaim 3 wherein said rotor is rotated by a stepper motor.
 9. The assaycartridge of claim 1 wherein said rotor comprises an instrumentinterface element.
 10. The assay cartridge of claim 3 wherein said topsurface comprises an instrument interface element.
 11. The assaycartridge of claim 10 wherein said bottom surface comprises said sealingmember.
 12. The assay cartridge of claim 1 wherein said stator and rotorengagement members are configured to move said rotor away from saidstator thereby disengaging said stator and rotor.
 13. The assaycartridge of claim 12 wherein said stator engagement member comprises atab and said rotor engagement member comprises a ramp, wherein said tabrides on said ramp to move said rotor away from said stator.
 14. Theassay cartridge of claim 13 wherein said ramp comprises an upward slopeand a downward slope.
 15. The assay cartridge of claim 14 wherein saidtab rides on said upward slope to move said rotor away from said statorand wherein said tab rides on said downward slope to move said rotortoward said stator.
 16. The assay cartridge of claim 11 wherein saidmulti-port valve is rotatable to selectively open one of said pluralityof valve outlets.
 17. The assay cartridge of claim 16 wherein said valveselectively opens one of said plurality of valve outlets by (a) rotatingsaid rotor via engagement between said stepper motor and said instrumentinterface element, and (b) disengaging said stator and rotor engagementmembers, thereby fluidically connecting said valve inlet to one of saidplurality of valve outlets through said fluidic connector and sealingthe remaining valve outlets via compression of said sealing memberagainst said stator.
 18. The assay cartridge of claim 1 wherein saidmulti-port valve comprises up to 20 valve outlets.
 19. The assaycartridge of claim 18 wherein said multi-port valve comprises up to 10valve outlets.
 20. The assay cartridge of claim 19 wherein saidmulti-port valve comprises up to 6 valve outlets.
 21. The assaycartridge of claim 1 wherein said rotor is rotated to fluidicallyconnect said valve inlet to two or more valve outlets through a fluidicconnector on said rotor while said sealing member seals the remainingvalve outlets.
 22. The assay cartridge of claim 1 wherein said sealingmember comprises an elastomer with a Shore A hardness of between about35 to
 90. 23. The assay cartridge of claim 1 wherein said sealing membercomprises an elastomer with a Shore A hardness of at least about
 40. 24.The assay cartridge of claim 1 wherein said sealing member comprises anelastomer with a Shore A hardness of at least about
 50. 25. The assaycartridge of claim 1 wherein said sealing member comprises an elastomerwith a Shore A hardness of at least about
 60. 26. The assay cartridge ofclaim 1 wherein said plurality of valve outlets are positioned in saidstator at a fixed radius from said valve inlet.
 27. The assay cartridgeof claim 26 wherein said fixed radius is about 0.1 to 0.4 inches. 28.The assay cartridge of claim 1 wherein said multi-port valve comprisesan internal dead volume of less than about 10 uL.
 29. The assaycartridge of claim 1 wherein said multi-port valve comprises an internaldead volume of about 7 uL.
 30. The assay cartridge of claim 1 whereinsaid rotor is a unitary element including said spring and said statorengagement member, and said sealing member is attached to said unitaryelement.
 31. The assay cartridge of claim 30 wherein said unitaryelement and/or said sealing member is/are injection molded.
 32. Theassay cartridge of claim 9 wherein said instrument interface elementcomprises a slot configured to communicate with a stepper motor in saidinstrument.
 33. The assay cartridge of claim 32 wherein said instrumentinterface element comprises one or more pin engagement slots configuredto communicate with one or more drive pins in said stepper motor. 34.The assay cartridge of claim 32 wherein said instrument interfaceelement comprises a multi-blade engagement slot configured tocommunicate with a multi-lobe drive element in said stepper motor. 35.The assay cartridge of claim 34 wherein said multi-blade engagement slotcomprises a three-blade engagement slot and said multi-lobe driveelement comprises three lobes.
 36. The assay cartridge of claim 1wherein said plurality of chambers comprises a sample chamber, adetection chamber, and a waste chamber.
 37. The assay cartridge of claim36 wherein said sample chamber is connected to a sample chamber conduitcomprising a filter outlet conduit connected to said valve inlet. 38.The assay cartridge of claim 1 wherein said cartridge comprises two ormore of said multi-port valves.
 39. The assay cartridge of claim 38wherein said two or more of said multi-port valves are connected inseries.
 40. A method of using a multi-port valve in an assay cartridge,wherein said cartridge comprises a plurality of chambers and a fluidicnetwork including (i) a plurality of fluidic conduits connecting saidplurality of chambers; and (ii) a multi-port valve comprising: (x) acap; (y) a stator comprising a rotor engagement member, a valve inlet,and a plurality of valve outlets accessible to one or more fluidicconduits in said fluidic network; and (z) a rotor biased toward saidstator and comprising a sealing member disposed between said rotor andsaid stator, a spring, an instrument interface element, and a statorengagement member configured to disengage said rotor when said statorengagement member is in communication with said rotor engagement member,said method comprising the steps of: (a) contacting said instrumentinterface element with an instrument stepper motor; (b) rotating saidrotor to disengage said rotor and stator engagement members; (c)connecting, fluidically, said valve inlet to one of said valve outletsthrough a fluidic connector on the rotor; and (d) sealing the remainingvalve outlets by contacting said sealing member to said stator.
 41. Themethod of claim 40 wherein said integrated spring comprises a topsurface, a bottom surface, a cylindrical body comprising a centralvertical axis disposed between said top and bottom surfaces and aplurality of pairs of axially spaced radially extending groovessurrounding said central vertical axis, and a plurality of through-holesintersecting said central vertical axis at a position perpendicular tothe intersection of said plurality of pairs of grooves to said centralvertical axis, and said sealing step (d) further comprises compressingsaid spring along said central vertical axis to seal said sealing memberto said stator.
 42. The method of claim 41 wherein said plurality ofpairs of grooves and said plurality of through-holes define a pluralityof ribs in said cylindrical body and said sealing step (d) comprisescompressing said plurality of ribs to seal said sealing member to saidstator.
 43. The method of claim 40 wherein said rotating step (b)comprises moving said rotor away from said stator thereby disengagingsaid stator and rotor engagement members.
 44. The method of claim 43wherein said stator engagement member comprises a tab and said rotorengagement member comprises a ramp, wherein said rotating step (b)comprises riding said tab on said ramp to move said rotor away from saidstator.
 45. The method of claim 44 wherein said ramp comprises an upwardslope and a downward slope, and said rotating step (b) comprises ridingsaid tab on said upward slope to move said rotor away from said stator.46. The method of claim 44 wherein said connecting step (c) furthercomprises riding said tab on said downward slope to move said rotortoward said stator, thereby fluidically connecting said valve inlet toone of said valve outlets through said fluidic connector on the rotor.47. A method of moving fluid in an assay cartridge comprising aplurality of chambers and a fluidic network including a plurality offluidic conduits connecting said plurality of chambers and a multi-portvalve having: (x) a cap; (y) a stator comprising a rotor engagementmember, a valve inlet, and a plurality of valve outlets accessible toone or more fluidic conduits in said fluidic network; and (z) a rotorbiased toward said stator and comprising a sealing member disposedbetween said rotor and said stator, a spring, an instrument interfaceelement, and a stator engagement member configured to disengage saidrotor when said stator engagement member is in communication with saidrotor engagement member, said method comprising the steps of: (a)introducing a fluid slug into said fluidic network; (b) applying,selectively, pressure or vacuum at one or more fluidic junctions in saidfluidic network to move said fluid slug through said fluidic network;and (c) directing movement of said fluid slug through said fluidicnetwork by engaging said multi-port valve to fluidically connect saidvalve inlet to one of said valve outlets through a fluidic connector onthe rotor while said sealing member seals the remaining valve outlets.